ES2784449T3 - Methods and apparatus for signaling and determining displacements of reference signals - Google Patents

Abstract

A method (600) of operation in a wireless communication device (12) configured to operate in a wireless communication network (16), the method (600) comprising: determining (602), based on information received from a node of network (50) in the network (16), a sequence offset for a sequence of reference signals (40); determining (604), as a function of the sequence offset, which part of the reference signal sequence (40) overlaps a planned bandwidth (36) of the wireless communication device (12), called the overlapping part (44) of the reference signal sequence (40), in which the planned bandwidth (36) is a part of a larger bandwidth of the system (30) associated with the network (16), and where the signal sequence reference (40) is superimposed on the bandwidth of the system (30) according to a mapping between respective sequence elements (42) that constitute the sequence of reference signals (40) and the respective subcarriers (32) that constitute the system bandwidth (30); and characterized by: transmitting one or more of the sequence elements (42) contained in the superimposed part (44) of the reference signal sequence (40).

Description

DESCRIPTION

Methods and apparatus for signaling and determining displacements of reference signals

Technical field

The present invention relates to communication networks and, in particular, relates to the determination of reference signal offsets in a communication network.

Background

Networks based on the long-term evolution specifications, LTE, promulgated by the Third Generation Partnership Project, 3GPP, use two types of reference signals: cell-specific or CRS reference signals, and demodulation or reference signals. DMRS, which are also denoted as DM-RS. CRSs span the entire involved bandwidth of the "system" and are "always on". In contrast, the DMRS covers only the planned bandwidth to which they belong and is only transmitted when data is transmitted.

The advantage of the reference signals that are always transmitted is that a wireless communication device, called UE or User Equipment in 3GPP language, can count on their presence. The drawbacks associated with CRS include high network power consumption because CRSs are transmitted even if no data is transmitted. CRS also creates unnecessary interference because it is transmitted even if it is not necessary.

See Figure 1, which illustrates an example of system bandwidth and transmission of CRS and DMRS within the system bandwidth. In an example of orthogonal frequency division multiplexing, OFDM, applicable to the LTE context, the system bandwidth comprises a plurality of separate narrow band subcarriers that together span the system bandwidth. Each subcarrier taken at each transmission time can be considered as a Resource Element, or RE, and it can be understood that figure 1 represents a part of an OFDM time frequency grid, with CRS and DMRS transmitting on specific subcarriers at specific times. specific. More particularly, regular CRS transmissions are observed across the system bandwidth, along with the transmission of DMRS in conjunction with the transmission of data on scheduled resources.

In LTE, the DRMS sequence element transmitted on a given subcarrier depends on the position of the subcarrier within the global plurality of subcarriers that make up the overall bandwidth of the system. For example, with subcarriers numbered 0 through N, the sequence element associated with the mth subcarrier depends on the value of m. This approach can be understood as a "global" numbering scheme that applies to system bandwidth, and more importantly, LTE UEs support global system bandwidth.

In more detail, in LTE, for any of the antenna ports pe {7,8, ..., u 6}, the reference signal sequence r ( m) used for DMRS on the subcarrier m within the blocks of r ^ max bandwidth resources, DL

downlink system, DL, m , is defined by

- 1 normal cyclic prefix

- 1 prefijo cíclico extendido

- 1 extended cyclic prefix

The pseudo-random sequence o (i) is defined by a Gold sequence of length 31.

The output sequence o ( n) of length M ^pn , where n = 0,1, ..., M ^pn -1, is defined by

c ( n) = (x1 («A, (^) + x2 (/ j A, ^) Jmod2

xt ( n +31) = (.T | (;? 3) xt (« n) ) Jrmod2

x (n + 31) = Ix («+3) x (« 2) + x («+ l) x,. («)} mod2

where Nc = 1600 and the first sequence m will be initialized with xi (0) = 1, xi (n) = 0, n = 1,2, ..., 30. The initialization of the cimt

equence m is denoted by = y *, (/) • 2 '

second, s ■, the application value depending on the sequence.

The pseudo-random sequence generator for DMRS in LTE is initialized with

at the beginning of each subplot.

The quantities ⁿ 10 '/' = 0.1, are given by

(/) _ iwxell DMRSj

• ^id ' ^{id if} there is no value for ^{id it} is provided by higher layers or if the DCI 1A, 2B or 2C format is used for the DCI associated with the PDSCH transmission

^{n (í) _} ^ DMR Yes

• 10 10 otherwise, where this value is indicated in the downlink control information used to plan the PDSCH. Here, "DCI" denotes downlink control information and "PDSCH" denotes physical downlink shared channel.

It is recognized here that certain complications arise with respect to the generation and use of DRMS signals in the context of NR, where "NR" denotes the New Radio standard contemplated in the current development of next generation communication networks, which is also used. known as 5G networks. NR contemplates wide bandwidths of the system, for example, bandwidths of 1 GHz or more, and not all terminals that operate in an NR system will have the ability to operate over the entire bandwidth of the system

NR will therefore provide support for terminals capable of supporting only a fraction of the system bandwidth. For example, the network configures a portion of the system bandwidth for use by the terminal, called the terminal configured bandwidth, and then uses the bandwidth within the configured bandwidth to schedule the terminal, called the terminal width. planned bandwidth of the terminal.

US2012 / 329468 A1 discloses a base station that aligns and transmits UE-specific reference signals (URS) in JP CoMP (MU JP CoMP) multi-user joint transmission / processing when the bandwidths of the Cooperating cells overlap but with different bandwidths.

Document US2017 / 005765 A1 describes the transmission of an uplink signal in a user equipment (UE) in a wireless communication system, generating a sequence of the reference signal based on the virtual cell ID, and transmitting the reference signal generated, to an eNB, over a planned bandwidth for uplink transmissions (UL).

A terminal can access an NR carrier by detecting a sync signal and a broadcast channel and performing a subsequent random access. After the random access, the network could set the terminal to a new frequency relative to the frequency used for the initial access. This approach does not require the terminal to know the system bandwidth or to know where, within the system bandwidth, its configured bandwidth lies.

Compendium

The methods and apparatus described in this document allow the use of demodulation reference signal sequences, DMRS, that are numbered in relation to an overall system bandwidth, while simultaneously allowing wireless communication devices to determine the elements of sequence DRMS mapped to your planned bandwidths within the system bandwidth. Advantageously, wireless communication devices do not need to know the system bandwidth or even know where their planned bandwidths reside within the system bandwidth.

The invention is defined by the appended claims 1-10. Embodiments which do not fall within the scope of the claims should be construed as useful examples in understanding the invention.

Brief description of the drawings

Figure 1 is an example diagram of CRS and DMRS transmission.

Figure 2 is a block diagram of one embodiment of a wireless communication network.

Figure 3 is a diagram of an embodiment of a defined mapping between a reference signal sequence and a system bandwidth.

Figure 4 is a diagram illustrating the resource elements corresponding to a time frequency grid.

Figure 5 is a block diagram illustrating example embodiments of a communication device wireless and a network node.

Fig. 6 is a logic flow diagram illustrating one embodiment of a processing method in a wireless communication device.

Figure 7 is a logic flow diagram illustrating one embodiment of a processing method at a network node. Figures 8 and 9 are diagrams illustrating example cases of victim and assailant devices that have planned bandwidth overlays.

Detailed description

Figure 2 illustrates one embodiment of a wireless communication network 16, "network 16". Network 16 provides one or more communication services to a wireless communication device 12, "device 12", such as by communicative coupling of device 12 to one or more external networks 14 such as the Internet or other packet data networks, PDN. Network 16 includes a Radio Access Network, RAN, 18. RAN 18 includes one or more radio network nodes 20, which may be called base stations, access points, transmission points, and so on. A core network, CN, 22 provides, for example, mobility management and packet routing for device 12, and includes one or more CN nodes 24, such as packet gateways, mobility management entities, authentication servers, etc. Network 16 may further include, or be associated with centralized or cloud-based processing nodes, that provide processing services for various functions within network 16.

It should be understood that the diagram is simplified, as network 16 may include multiple other nodes of the same or different type, and may include multiple radio network nodes 20, and may include more than one RAN, and may operate with more than one Technology. radio access, RAT. In one example, the different types of radio network nodes 20 provide a heterogeneous radio access network, which may involve more than one RAT. Furthermore, in the context of 5G new radio, NR implementations, network 16 may use beamforming, for example, where beams allocated within a potentially large plurality of beams from one or more network nodes Radio 20 are used to provide coverage to device 12.

Still further, unless otherwise indicated, the terms "device", "wireless communication device", "user equipment" and "UE" are used interchangeably herein. Unless otherwise specified, device 12 essentially comprises any apparatus configured to connect wirelessly to network 16 through one or more of the Radio Access Technologies, RATs, used by network 16. Device 12 It can be mobile, although fixed devices are also contemplated and non-limiting examples include cellular radiotelephones, which can be smartphones or functional phones, laptops, tablets, wireless modems or adapters, machine-to-machine, M2M or machine-type communication devices, MTC, internet of things, IoT, devices, etc.

Figure 3 represents an example of embodiment contemplated in the context of device 12 and network 16, where a bandwidth of system 30 is associated with network 16. As a non-limiting example, the bandwidth of the system represents the width of air interface band supported by a radio network node 20 in RAN 18, which functions as a transmission point NR or transceiver. Device 12 supports a fraction of the bandwidth of system 30, which constitutes a plurality of frequency subcarriers 32. Subcarriers 32 can be numbered low to high frequency, high to low frequency, or according to some other ordered scheme. Therefore, FIG. 3 can be considered to represent a scenario where the operational bandwidth capabilities of the radio network node 20 differ from the operational bandwidth capabilities of the device 12.

Device 12 is associated with a configured bandwidth 34, which is configured by network 16, which is contained within the bandwidth of system 30 but is compatible with the bandwidth limitations of device 12. Network 16 schedules device 12 for data transmissions or receptions, using a planned bandwidth 36, which is compatible with configured bandwidth 34. A given node 20 in RAN 18 can support many devices 12 within its system bandwidth 30 and can locate the corresponding configured bandwidths 34 at various positions within the overall system bandwidth 30)

As a non-limiting example, the collection of subcarriers 32 shown constituting the bandwidth of system 30, which is viewed on the left side of the page, may be numbered according to some global scheme. Correspondingly, a sequence of reference signals 40, viewed on the right side of the page, is mapped to, or aligned with, the bandwidth of system 30. The correspondence between the respective sequence elements 42 in the The sequence of reference signals 40 and the respective subcarriers 32 in the bandwidth of the system 30 is suggested by the horizontal alignment shown between the two in the diagram.

However, the depicted mapping is shown by way of example and not limitation, and it will be appreciated that the general idea here is that there is a definite association between the subcarriers 32 in the bandwidth of the system 30 and the sequence elements 42 in the sequence of reference signals 40. In one example, the sequence of Reference signals 40 comprise a DMRS sequence generated such that each sequence element 42 depends on the number of its corresponding subcarrier 32, subcarriers 32 that are numbered within the bandwidth of the "global" system 30. See, for example, The Scheme of DMRS sequence generation explained in the Background of this disclosure for LTE.

Within this framework, then, the sequence elements 42 that correspond to the subcarriers 32 included within the planned bandwidth 36 of a given device 12 depend on where the planned bandwidth 36 is located within the system bandwidth 30. In the example shown, the configured bandwidth 34 of the device 12 is located at a frequency offset relative to a starting point of the system bandwidth 30, and the planned bandwidth 36 is located at a further offset. in relation to the start of the configured bandwidth 34. Here, it can be seen that the size and position of the planned bandwidth 36 may vary within the configured bandwidth 34, as part of the ongoing planning operations. Referring to the global numbering of the system 30 bandwidth, the configured bandwidth 34 starts at point A in the system 30 bandwidth and goes to point C in the system 30 bandwidth, while the Planned bandwidth 36 runs from points B to C.

Because the reference signal sequence 40 maps to, corresponds to, or "overlaps" the bandwidth of the system 30, according to a defined mapping, a particular portion 44 of the reference signal sequence 40 is overlaps the planned bandwidth 36 of device 12. According to the labeling, the sequence elements 42 running from point E to point F in the reference signal sequence 40 are superimposedly mapped to the subcarriers 32 going from point B to C in the bandwidth of system 30. More generally, the sequence segment from point D to F overlaps the bandwidth segment from point A to C.

Figure 4 illustrates another view of the bandwidth of system 30, this time shown in the context of a time frequency grid, where the intersection between transmission times and subcarriers 32 represents "resource elements" or RE 38. The transmission or reception of a sequence element 42 on its corresponding subcarrier 32 will be understood to mean the transmission or reception on a resource element 38 defined on that subcarrier 32.

With the above framework in mind, the methods and apparatus described in this document allow the device 12 to determine the overlapping portion 44 of the reference signal sequence 40, without having to know the bandwidth of the system 30. In at least some embodiments , the device 12 determines the overlapping portion 44 of the reference signal sequence 40 without explicit knowledge of where its planned bandwidth 36 is located within the system bandwidth 30.

Figure 5 depicts exemplary embodiments of a device 12 and a network node 50, which are configured to carry out the respective device-side and network-side operations described herein. Node 50 can be implemented in various network locations, such as RAN 18, CN 22, or as a cloud-based node 26. Furthermore, node 50 can comprise two or more nodes, that is, its functionality can be distributed. In at least one embodiment, node 50 is co-located or implemented in radio network node 20 seen in Figure 2, and it will be understood that there may be multiple such nodes 20 in network 16.

Wherever it is implemented, in an exemplary embodiment, node 50 includes communication circuits 52 that are configured to communicate directly or indirectly with device 12. For example, communication circuits 52 include transceiver circuits, i.e., transceiver circuits. radio frequency, RF, transmission and reception configured to transmit signals on the downlink to one or more devices 12 and to receive signals on the uplink from said devices 12. Additionally or alternatively, the communication circuits 52 include one or more interfaces of network or computer data, to communicate with one or more other nodes in the network 16. In at least one such example, node 50 communicates indirectly with device 12 by sending signaling to another node that provides the air interface for wireless coupling to device 12.

Node 50 further includes processing circuits 54 that are operatively associated with communication circuits 52 and include, or are associated with storage 56. Processing circuits 54 comprise fixed circuits, or programmed circuits, or a mixture of fixed circuits and scheduled. In at least one embodiment, the processing circuits 54 comprise one or more microprocessors, digital signal processors, DSPs, field programmable gate arrays, FPGAs, application specific integrated circuits, ASICs, or other digital processing circuits. In at least one such embodiment, the processing circuitry 54 is configured in accordance with the teachings herein based on its execution of computer program instructions stored in one or more computer programs 58 contained in storage 56. The storage 56 may further contain one or more items of configuration data 60 that are pre-arranged in, and / or dynamically acquired by, the processing circuits 54. In one or more embodiments, the storage 56 comprises one or more types of readable media. computer, such as a mix of non-volatile memory or disk storage circuits, along with working memory, volatile. Non-limiting examples of non-volatile storage include solid state disk, SSD, storage, FLASH, and EEPROM, while non-limiting examples of working memory, volatile, include DRAM or SRAM circuitry.

In at least one embodiment, communication circuits 52 are configured to communicate directly or indirectly with a device 12 operating on network 16, and processing circuits 54 are operatively associated with communication circuits 52 and configured to perform various functions. or operations. Processing circuitry 54 is configured to determine a value from which device 12 can determine which part of a sequence of reference signals 40 overlaps a planned bandwidth 36 of device 12.

As before, that part of the reference signal sequence 40 is known as an overlapping part 44, and the planned bandwidth 36 is in a configured bandwidth 34 that is configured for the device 12. In turn, the width The configured bandwidth 34 is within the bandwidth of the system 30. A defined mapping determines the correspondence between the sequence 40 and the bandwidth of the system 30, that is, it defines a mapping between the respective sequence elements 42 that constitute the sequence of reference signals 40 and the respective subcarriers 32 that make up the bandwidth of the system 30. Here, the configured bandwidth 34 for the wireless communication device 12 can be configured by the processing circuitry 54. Similarly, the Planned bandwidth 36 can be dynamically selected by the processing circuits 54, as part of a planning function implemented therein.

The processing circuitry 54 is further configured to signal the value to the device 12, thus allowing the device 12 to determine the overlapping portion 44 of the reference signal sequence 40 and correspondingly identify which sequence elements 42 of the reference signal sequence 40 are associated with subcarriers 32 in planned bandwidth 36. For example, the value may be signaled to device 12 along with the configured bandwidth setting 34.

The processing circuitry 54 in one example determines the value as a seed value to initiate a sequence element generation function in the wireless communication device. Because the initialization value controls where the generator "starts" in the sequence of reference signals 40, the processing circuitry 54 may implicitly provide the device 12 with the applicable sequence offset. That is, the processing circuits 54 can provide the device 12 with the initialization value corresponding to the start of its configured bandwidth 34, so that the generation of the sequence element in the device 12 begins with the first sequence element 42 in the configured bandwidth 34.

Because the device 12 knows the position of its planned bandwidth 36 within the configured bandwidth 34, knowing the initial sequence element 42 means that it knows the sequence elements 42 that correspond to the subcarriers 32 in its bandwidth. planned 36, that is, it knows the overlapping part 44 of the reference signal sequence 40. Advantageously, the approach works without the device 12 having to know the bandwidth of the system 30 and without the device having to know the position of your configured bandwidth 34 within the system bandwidth 30. Significant reductions in signaling overhead and complexity of bandwidth management put the spotlight on focus.

In another example, the processing circuitry 54 is configured to determine the value that the device 12 signals as an offset value that identifies a sequence offset corresponding to the overlapping portion 44 of the reference signal sequence 40, or that identifies a position offset of the configured bandwidth 34 within the system bandwidth 30. In the latter case, the sequence offset can be obtained in the wireless communication device 12. In a similar approach, the processing circuits 54 are configured to determine the value as an offset value that relates the configured bandwidth 34 to a reference position within the system bandwidth 30.

In the same or another embodiment and with respect to an uplink transmission received on network 16 from a device 12, processing circuitry 54 is configured to determine which sequence elements of a sequence of uplink reference signals are included. , or interfere with the uplink transmission. The determination is based on a position of the planned bandwidth 36 within the bandwidth of the system 30 and the defined mapping.

Although device 12 may be less complex than node 50, it may similarly comprise digital processing circuitry and associated communication circuitry. Starting from the example of Figure 5, device 12 includes communication circuits 72 that are configured to receive downlink signals from network 16 and transmit uplink signals to network 16. For example, communication circuits 72 include Radio frequency, RF transceiver circuits configured to transmit on the uplink to one or more radio network nodes 20 and to receive on the downlink from one or more radio network nodes 20. Communication circuits 72 may also support device-to-device communications, D2D, directly with other devices 12 and can include WLAN communications, Bluetooth communications, near field communication, NFC, etc.

Device 12 further includes processing circuits 74 that are operatively associated with communication circuits 72 and include, or are associated with storage 76. Processing circuits 74 comprise fixed circuits or programmed circuits, or a mixture of fixed and programmed circuits. . In at least one embodiment, the processing circuits 74 comprise one or more microprocessors, DSP, FPGA, ASIC, or other digital processing circuitry.

In at least one such embodiment, the processing circuitry 74 is configured in accordance with the teachings herein based on the execution of instructions from computer programs stored in one or more computer programs 78 contained in storage 76. The storage 76 may further contain one or more items of configuration data 80 that are pre-arranged, and / or dynamically acquired by, the processing circuits 74. The configuration data 80 includes, for example, the value signaled to device 12 by the network 16, to determine the overlapping portion 44 of the reference signal sequence 40.

In one or more embodiments, storage 76 comprises one or more types of computer-readable media, such as a mixture of non-volatile memory circuitry or disk storage and volatile working memory. Non-limiting examples of non-volatile storage include SSD, FLASH, and EEPROM storage, while non-limiting examples of volatile working memory include DRAM or SRAM circuitry.

Communication circuits 72 are configured to communicate wirelessly with one or more nodes in network 16, for example, with one or more radio network nodes 20. Processing circuits 74 are operatively associated with communication circuits 72 , for example, they obtain data or control information by input of received signals entering communication circuits 72, and send data or control information by means of transmitted signals, from communication circuits 72. In addition, the Processing circuits 74 are configured to determine, based on information received from network 16, a sequence offset for a reference signal sequence 40 and determine, based on the sequence offset, which part of the reference signal sequence 40 overlaps a planned bandwidth 36 of device 12.

The overlapping portion called the overlapping portion 44 of the reference signal sequence 40 and, as noted above, the planned bandwidth 36 is a part of a larger system 30 bandwidth associated with the network 16. In this context, the sequence of reference signals 40 is superimposed on the bandwidth of the system 30 according to a defined mapping between the respective sequence elements 42 that constitute the sequence of reference signals 40 and the respective subcarriers 32 that constitute the bandwidth of the system 30.

In an exemplary embodiment, the processing circuitry 74 is configured to perform at least one of: transmitting one or more of the sequence elements 42 contained in the overlapping portion 44 of the reference signal sequence 40; decoding, based on one or more of the sequence elements 42 contained in the superimposed portion 44 of the sequence of reference signals 40; canceling the interference based on one or more of the sequence elements 42 contained in the overlapping portion 44 of the reference signal sequence 40; and estimating a channel, based on one or more of the sequence elements 42 contained in the overlapping portion 44 of the reference signal sequence 40.

In at least some embodiments, information received from network 16 directly or indirectly indicates a position of a configured bandwidth 34 within the bandwidth of system 30. Consequently, processing circuitry 74 is configured to determine the offset of sequence based on the position of the configured bandwidth 34 and a position of the planned bandwidth 36 within the configured bandwidth 34. That is, the position of the configured bandwidth 34 within the bandwidth of the system 30 defines a first offset in the sequence of reference signals 40, and the position of the planned bandwidth 36 within the configured bandwidth 34 defines a further offset in the sequence of reference signals 40.

Network 16 may also provide a seed value as the information used by processing circuitry 74 to determine the sequence offset. Here, the processing circuitry 74 is configured to determine the sequence offset implicitly, using the initialization value to initialize a sequence element generation function, where the initialization value is a function of the sequence offset. In operation, the sequence item generation function, initialized by the initialization value, generates sequence items 42 corresponding to the configured bandwidth 34 of device 12. The planned bandwidth 36 is within the configured bandwidth 34 and the processing circuitry 74 is configured to determine the overlapping portion 44 of the reference signal sequence 40, based on a position of the planned bandwidth 36 within the configured bandwidth 34.

In another example, information received from network 16 indicates an offset that relates a position of a configured bandwidth 34 of device 12 to a reference position within the bandwidth of system 30, eg, a reference subcarrier. Accordingly, the processing circuits 74 are configured to determine the sequence offset as a function of the position of the configured bandwidth 34 relative to the reference position, and further based on a position of the planned bandwidth 36 within the configured bandwidth 34.

Knowing which sequence elements 42 correspond to subcarriers 32 in its planned bandwidth 36 allows device 12 to perform one or more receive and / or transmit operations. For example, knowing which sequence element 42 maps to a given subcarrier 32 within its planned bandwidth 36 allows processing circuits 74 to estimate the interference arising at device 16 from receiving that sequence element 42 from another. node or device on the network 16.

Here it should be understood that there may be more than one sequence element 40 defined within network 16, eg, a base sequence and one or more cyclically shifted versions of the base sequence. If all those sequences 40 have the same element-to-subcarrier mapping defined relative to the bandwidth of system 30, device 16 may not know precisely which sequence element 42 it receives as interference, but it will know the set of possible elements of sequence 42, which greatly limits the number of interference hypotheses you need to consider.

Therefore, in at least some embodiments, the processing circuitry 74 is configured to estimate the interference in the device 12, as a result of a transmission of reference signals by another device or node, based on one or more of the elements sequence 42 contained in the superimposed part 44 of a sequence of reference signals 40. The sequence elements 42 contained in the superimposed part 44 of the reference signal sequence 40 depend on a cyclic offset used by the interfering node or device, and the processing circuitry 74 is configured to estimate the interference by hypothesizing the cyclic shift in accordance with a known set of possible cyclic shifts.

Figures 6 and 7 depict exemplary embodiments of processing at a device 12 and a network node 50, respectively. Method 600, performed by a device 12, includes determining (Block 602), based on information received from network 16, a sequence offset for a sequence of reference signals 40, and determining (Block 604), based on from the sequence offset, which part of the reference signal sequence 40 overlaps a planned bandwidth 36 of the device 12. The method 600 may further include a prior step or operation of receiving the information in question, such as during a configuration operation in which network 16 determines the configured bandwidth 34 of device 16.

Method 700, when performed by a network node 50, includes determining (Block 702) a value from which a device 12 can determine which part of a sequence of reference signals 40 overlaps a planned bandwidth 36 of device 12, and signaling (Block 704) the value for device 12. As before, planned bandwidth 36 is contained within a configured bandwidth 34 of device 12, and method 700 may further include a step or configured bandwidth setting operation 34 for device 12 and value signaling for device 12 may occur in conjunction with bandwidth setting operations. The signaling of such information to the device 12 allows the device 12 to determine the overlapping portion 44 of the reference signal sequence 40 and correspondingly identify which sequence elements 42 of the reference signal sequence 40 are associated with the subcarriers 32 in the width of planned band 36.

In further example details for at least some embodiments, an offset parameter, which may also be referred to as a "value" or "information," is signaled from network 16 to device 12, allowing device 12 to determine the element of sequence 42 of a sequence of reference signals 40 that overlap with its planned bandwidth 36 or its configured bandwidth 34. The sequence of reference signals 40 is, for example, a DMRS sequence, and its sequence elements are numbered globally, for example, relative to the bandwidth of system 30. Device 12 may not know the bandwidth of system 30.

With the reference signal sequence 40 and its constituent sequence elements 42 referred to as a DMRS sequence and DMRS sequence elements, one possibility is that the flagged parameter allows the device 12 to determine the DMRS sequence element that is mapped to the frequency lower than your configured bandwidth 34. The offset parameter indicates the start of the DMRS sequence, for example. The offset parameter could, of course, be set to indicate the DMRS sequence element mapped to other positions, such as highest frequency, middle frequency, etc.

Figure 8 depicts a corresponding example involving a victim device 12 and two attacker devices, for example, victim device 12 is a first UE and the two attacker devices are other nearby UEs. Based on the flagged parameters, the device 12 can determine that the DMRS sequence element 3 is the sequence element that is mapped to the first DMRS position within its configured bandwidth 34. Then, in the simplest case, the parameter signaled to device 12 by network 16 it could indicate "3".

The parameter -3 signaled in the example- together with the scheduling assignment, which is generally relative to the configured bandwidth 34 of the device, allows the device 12 to determine the DMRS sequence positions that correspond to the frequency positions represented by its planned bandwidth 36. That is, in Figure 8, receiving the signaled value of "3" from network 16 allows device 12 to know that the lower frequency position of its configured bandwidth 34 is "3", which corresponds to the sequence position DMRS 3, DRMS3. Since device 12 knows the position of its planned bandwidth 36 within the configured bandwidth 34, device 12 knows that the frequency positions contained in its planned bandwidth correspond to, or are mapped to, the DMRS sequence positions 4 , 5 and 6.

The actual values of the DMRS sequence elements that are mapped to their planned bandwidth 36 can be derived from device 12 specific parameters and / or cell parameters, such as the virtual cell ID. In principle, it is also possible that the flagged parameter directly indicates the first, or a specified DMRS sequence element of the planned bandwidth 36 instead of the configured bandwidth 34. However, there may be certain advantages associated with the parameter relationship with the configured bandwidth 34. For example, the parameter would have to be signaled only with changes in the configured bandwidth 34.

If device 12 only supports a fraction of the bandwidth of system 30, device 12 is configured with a bandwidth after device 12 makes an initial access. In at least one embodiment, the parameter required to determine the alignment of DMRS sequences with the planned bandwidth 36 of the device can be obtained at the device 12 from the configuration and no explicit signaling is needed.

In a related embodiment, a reference subcarrier is defined in the bandwidth of system 30. For example, the primary synchronization signal, PSS, is transmitted by network 16 and received and detected by device 12. The center position of the detected PSS can be identified as the reference subcarrier or, more generally, any subcarrier 32 in the bandwidth of system 30 can be defined as a reference subcarrier. The operational bandwidth that is configured for device 12 is signaled, indicating a frequency distance relative to reference subcarrier 32. The distance can be indicated in terms of subcarriers 32, or corresponding resource blocks, and the like.

The DMRS sequence r ( m) is generated by subcarrier m with respect to the reference subcarrier, where m can be both positive and negative, to create a global numbering scheme. Knowing the frequency distance from the reference subcarrier, even though it is outside the operating bandwidth for device 12, allows device 12 to determine the DMRS sequence for its planned resource blocks.

Consider the attacker devices 1 and 2 seen in Figure 8 below. Each attacker device has a planned bandwidth that at least partially overlaps the planned bandwidth 36 of device 12. With the global numbering scheme, any position The frequency that is common between the planned bandwidth 36 of the device 12 and the attacking devices 1 and 2 will be mapped to the same DMRS sequence position. Therefore, if device 12 knows what DMRS sequences might be in use on the attacking devices, it knows exactly what DMRS sequence items could be received on device 12 from attacking devices, on subcarriers 32 included in its planned bandwidth. 36.

For example, there may be a limited number of defined DMRS sequences, eg, using a base DMRS sequence and a defined set of cyclic shifts. Each cyclic shift can be considered to produce a different DMRS sequence. However, all sequence elements in each DMRS sequence observe global mapping, that is, the sequence positions in each DMRS sequence are mapped to the system bandwidth frequency positions by the same global mapping and numbering. Therefore, the actual value of the sequence element at sequence position "x" in a first DMRS sequence will differ from the value of the sequence element at sequence position "x" in a second DMRS sequence. However, the sequence position "x" of both sequences is mapped to the same frequency position in the overall system bandwidth. Therefore, assuming as a simplified example that there are five DRMS sequences that could be used by a transmitter, there are no more than five possible values of sequence elements that the transmitter could transmit at the sequence position "x". Correspondingly, for a subcarrier 32 corresponding to sequence position "x", a receiver receiving interference from those transmissions could limit its interference assumptions to the set of five possible sequence element values.

In other words, if the device 12 knows the DMRS sequences that can be used in the attacking devices - for example, it knows the possible cyclic shifts - it knows the universe of possible values for the DRMS sequence element or elements that it receives on the corresponding subcarrier 32 to the sequence position involved. As seen in the figure, due to the global numbering of the DMRS sequence elements, the interfering DMRS sequence elements from the attacking devices 1 and 2 that overlap the planned bandwidth 36 of the device 12 are also elements 4 to 6 To cancel DM-RS interference, device 12 only needs to test one or a few sequence candidates, but not different positions. sequence. The device 12 could, for example, know the cell ID of neighboring transmission points, for example, radio network nodes 20, and obtain one or a few DM-RS sequences connected to the transmission point from the virtual cell ID of that transmission point.

Another possibility for the network 16 to provide the information that the device 12 needs to determine the DMRS sequence positions that correspond to the frequency positions of its planned bandwidth 36 is to signal a seed value. Often times, the sequence used for DMRS is a pseudo-random sequence generated by a pseudo-random sequence generator that is initialized with a specified seed value, for example, c init. The pseudo-random sequence generator could be initialized with a seed value and generates a sequence that is then mapped to the overall DMRS sequence starting with sequence element 0, which maps to the lowest DM-RS element within the bandwidth of the system 36.

In Figure 8, the fourth sequence element is the first DM-RS element within the configured bandwidth 34 of device 12. Therefore, the pseudo-random sequence generator in device 12 could be configured with the initialization value that produces the same pseudo-random sequence but starting with sequence element 4, labeled DMRS3 in the diagram.

In a further embodiment, there is a set of possible initialization values c_init, corresponding to a set of reference subcarriers within the system bandwidth. Device 12 signals the offset to the closest reference subcarrier and the identity of the reference subcarrier. To generate the DMRS sequence r ( m), corresponding to a c init, it is necessary to store the values of the shift register. For example, if sequences m are used as in LTE, x_1 (n), x_2 (n) have to be stored for an interval of n. A device 12 can store the shift register memory values corresponding to sequence elements mapped to a set of reference subcarriers, for example, 100 MHz apart. Depending on whether device 12 is located from 0 to 100 MHz (original c init) or from n * 100 to (n 1) * 100 MHz (n = 1,2,3, three values of c_init), this would initialize the random generator with the original c_init or with one of the other three values of c_init. The benefit of this is that direct generation of a sequence would be limited to a maximum of 100 MHz, which is the longest distance from the configured bandwidth 34 of the device to a reference subcarrier. Otherwise, for very large system bandwidths, eg 1 GHz, direct generation of the sequence r ( m) at the configured bandwidth 34 would be complicated.

Generally speaking, the network 16 in one or more embodiments is configured to signal a parameter to a device 12 which the device 12 uses to determine its reference signal, that is, to determine which part of a sequence of reference signals corresponds to its planned bandwidth 36. This arrangement allows device 12 to determine which DMRS sequence elements apply to planned bandwidth 36, without device 12 having to know the bandwidth of system 30 or the position of its bandwidth. planned band 36 within the bandwidth of the system 30. Such an approach allows the network 16 to relate or map DMRS sequence positions with frequency positions in the bandwidth of the system 30 using a global numbering scheme.

The parameter signaled by network 16 to a device 12 could be an offset parameter that informs device 12 which part to "cut" from a global DMRS sequence, for example, it could be the reference signal sequence element number that is mapped to the beginning of the configured bandwidth 34 of device 12. This parameter, along with the device's knowledge of where its planned bandwidth 36 is within its configured bandwidth 34, would allow device 12 to determine the sequence elements of reference signals mapped to their planned bandwidth 36. The flagged parameter could also be an initialization parameter that informs device 12 how to initialize its pseudo-random sequence generator, assuming a pseudo-random sequence is used for DM-RS. The first generated sequence element would again correspond to the reference signal sequence element mapped to the beginning of the configured bandwidth of device 34.

Such operations allow a global numbering of DMRS sequences in relation to the system bandwidth, even if the device 12 does not know the bandwidth of the system 30 or its bandwidth position in relation to the bandwidth of the system 30 Regardless of the frequency position of the victim and the attacker, a victim device 12 knows which numbers of sequence elements in the attacker's DM-RS sequence overlap its planned bandwidth 36 and can therefore easily cancel the attack. Interfering DMRS. In the simplest case, the DMRS only depends on the cell ID or a similar parameter, such as the virtual cell ID; If the victim device 12 knows the cell ID of the interfering node, it also knows the interfering sequence elements. In a practical configuration, a given transmission point can be associated with a cell ID, but can create pseudo-orthogonal reference signals. Even in this case, if the victim device 12 knows the cell ID, it only has to try a few candidate sequences to cancel the interference that arises in the device 12 from the transmission of the reference signal (s) by the transmission point. .

Figure 9 emphasizes this scenario by showing the overall alignment between the signal sequence positions of reference for a victim device 12 and two attacker devices 1 and 2. In particular, it is seen that the same sequence position numbering - which is generally related to the frequency position numbering of the system bandwidth 30 - is applied to the victim device 12 and attacker devices 1 and 2. That is, part 44-1 of a reference signal sequence that overlaps the planned bandwidth of victim device 12 uses the same sequence numbering / position mapping as used for parts 44-2 and 44-3 that overlap the planned bandwidths of attacking devices 1 and 2. It should be noted that the actual reference signal sequences are not necessarily the same for all three devices. That is, the sequence position associated with sequence element 4 in each of the overlapping parts 44-1, 44-2 and 44-3, may have a different value, but the alignment or mapping of that sequence position is same for all three devices.

Having a broad understanding of the above details, one or more sequences of reference signals 40 are available or defined for use in a wireless communication network 16. Each sequence of reference signals 40 comprises a series or set of sequence elements 42 , each sequence element occupying a corresponding position in the sequence of reference signals 40. Network 16, for example, a given radio network node 20, uses a global numbering scheme for its system 30 bandwidth, for For example, a global numbering scheme for the frequency subcarriers 32 that make up its system 30 bandwidth. Each subcarrier 32 can be considered to occupy a frequency position, and the network 16 uses a defined mapping that relates the positions of the reference signals with frequency positions. A device 12 is configured with a configured bandwidth 34, where the configured bandwidth 34 is located somewhere within the bandwidth of the system 30. In operation, the device 12 uses a planned bandwidth 36 that occupies the all or a portion of the configured bandwidth 34. Due to the defined mapping or alignment between the reference signal sequence positions and the frequency positions, the sequence positions that correspond to the frequency positions associated with the signal width The planned bandwidth 36 of the device is dictated by where the planned bandwidth 36 is located within the bandwidth of the system 30. However, in accordance with the teachings herein, the device 12 need not know the bandwidth of the device. system band 30, not even knowing the position of your configured / planned bandwidth 34/36, to know which signal sequence positions of r eference correspond to its planned bandwidth 36. Network 16 avoids these needs by signaling information to device 12, from which device 12 can implicitly or explicitly determine the sequence offset corresponding to its system bandwidth 36.

The invention is defined by the appended claims 1-10.

Claims (10)

1. A method (600) of operation in a wireless communication device (12) configured to operate in a wireless communication network (16), the method (600) comprising: determining (602), based on information received from a network node (50) in the network (16), a sequence offset for a sequence of reference signals (40); determining (604), as a function of the sequence offset, which part of the reference signal sequence (40) overlaps a planned bandwidth (36) of the wireless communication device (12), called the overlapping part (44) of the reference signal sequence (40), wherein the planned bandwidth (36) is a part of a larger system bandwidth (30) associated with the network (16), and where the reference signal sequence (40) overlaps the bandwidth of the system (30) according to a mapping between respective sequence elements (42) that constitute the sequence of reference signals (40) and the respective subcarriers (32) that constitute the bandwidth of the system (30); and characterized by : transmitting one or more of the sequence elements (42) contained in the overlapping portion (44) of the reference signal sequence (40). The method (600) according to claim 1, wherein the information received from the network node (50) indicates a position of a configured bandwidth (34) within the bandwidth of the system (30), and wherein determining (602) the sequence offset comprises determining the sequence offset based on a configured bandwidth position (34) and a planned bandwidth position (36), wherein the planned bandwidth (36) is contained within the configured bandwidth (34). The method (600) according to claim 1, wherein the information received from the network node (50) indicates an initialization value, and wherein determining (602) the sequence offset comprises determining the sequence offset using the initialization value to start a sequence element generation function, where the initialization value is a function of the sequence offset. The method (600) of any of claims 1-3, wherein the mapping maps the respective sequence elements (42) that constitute the reference signal sequence (40) to respective subcarriers (32) that constitute the system bandwidth (30). The method (600) according to claim 1, wherein the information received from the network node (50) indicates an offset that relates a position of a configured bandwidth (34) of the wireless communication device (12) to a reference position within the bandwidth of the system (30), and wherein determining (602) the sequence offset comprises determining the sequence offset as a function of the position of the configured bandwidth (34) in relation to the reference position, and also as a function of a position of the planned bandwidth (36) within the configured bandwidth (34). 6. A wireless communication device (12) configured to operate in a wireless communication network (16) and comprising: communication circuits (72) configured to communicate wirelessly with one or more nodes in the network (16); Y processing circuits (74) operatively associated with communication circuits (72) and configured to: determining, based on information received from a network node (50) in the network (16), a sequence offset for a sequence of reference signals (40); Y determining, based on the sequence offset, which part of the reference signal sequence (40) overlaps a planned bandwidth (36) of the wireless communication device (12), called the overlapping part (44) of the sequence of reference signals (40); where The planned bandwidth (36) is a part of a larger bandwidth of the system (30) associated with the network (16) and where the sequence of reference signals (40) overlaps the bandwidth of the system (30 ) according to a mapping between respective sequence elements (42) that constitute the sequence of reference signals (40) and respective subcarriers (32) that constitute the bandwidth of the system (30); and characterized by being configured to transmit one or more of the sequence elements (42) contained in the superimposed portion (44) of the reference signal sequence (40). The wireless communication device (12) according to claim 6, wherein the information received from the network node (50) indicates a position of a configured bandwidth (34) within the bandwidth of the system (30), and wherein the processing circuits (74) are configured to determine the sequence offset based on a configured bandwidth position (34) and a planned bandwidth position (36), in that the planned bandwidth (36) is contained within the configured bandwidth (34). The wireless communication device (12) according to claim 6, wherein the information received from the network node (50) indicates an initialization value, and wherein the processing circuitry (74) is configured to determine the sequence offset, using the initialization value to initialize a sequence element generation function, where the initialization value is a function of the sequence offset. Wireless communication device (12) according to any one of claims 6 to 8, wherein the mapping maps respective sequence elements (42) that constitute the sequence of reference signals (40) to respective subcarriers (32) that constitute the system bandwidth (30). The wireless communication device (12) according to claim 6, wherein the information received from the network node (50) indicates an offset relating a position of a configured bandwidth (34) of the wireless communication device ( 12) with a reference position within the bandwidth of the system (30), and in which the processing circuits (74) are configured to determine the sequence offset as a function of the position of the configured bandwidth (34) in relation to the reference position, and also as a function of a position of the planned bandwidth (36) within the configured bandwidth (34).